There are many good education agents that are not licensed immigration advisors. They are still experts that can help you with your student visa application. It is important that you receive clear and accurate advice as the wrong immigration advice could have serious consequences.
In the UK licensed advisors will be registered with the Office of the Immigration Services Commissioner (OISC) or the Law society.
In Canada licensed advisors will be registered with the College of Immigration and Citizenship Consultants (CICC) or the Canadian provincial or territorial law society.
In Australia licenced advisors will be registered with Migration Agents Registration Authourity (MARN) or a qualified legal practitioner.
Check with government sources in your own country and beware of trusting unverified information such as online forums.